Provide setting for delete-check autocommands.

README.md

@@ -102,6 +102,7 @@ Neovim >= 0.5 (extmarks)
 - `history`: If true, Snippets that were exited can still be jumped back into. As Snippets are not removed when their text is deleted, they have to be removed manually via `LuasnipUnlinkCurrent`.
 - `updateevents`: Choose which events trigger an update of the active nodes' dependents. Default is just `'InsertLeave'`, `'TextChanged,TextChangedI'` would update on every change.
 - `region_check_events`: Events on which to leave the current snippet if the cursor is outside its' 'region'. Disabled by default, `'CursorMoved'`, `'CursorHold'` or `'InsertEnter'` seem reasonable.
+- `delete_check_events`: When to check if the current snippet was deleted, and if so, remove it from the history. Off by default, `'TextChanged'` (perhaps `'InsertLeave'`, to react to changes done in Insert mode) should work just fine (alternatively, this can also be mapped using `<Plug>luasnip-delete-check`). 
 - `store_selection_keys`: Mapping for populating `TM_SELECTED_TEXT` and related variables (not set by default).
 - `enable_autosnippets`: Autosnippets are disabled by default to minimize performance penalty if unused. Set to `true` to enable.
 - `ext_opts`: Additional options passed to extmarks. Can be used to add passive/active highlight on a per-node-basis (more info in DOC.md)

lua/luasnip/config.lua

@@ -6,6 +6,7 @@ local defaults = {
 	updateevents = "InsertLeave",
 	-- see :h User, event should never be triggered(except if it is `doautocmd`'d)
 	region_check_events = "User None",
+	delete_check_events = "User None",
 	store_selection_keys = nil, -- Supossed to be the same as the expand shortcut
 	ext_opts = {
 		[types.textNode] = {
@@ -78,14 +79,15 @@ c = {
             au!
             autocmd %s * lua require("luasnip").active_update_dependents()
             autocmd %s * lua require("luasnip").exit_out_of_region(Luasnip_current_nodes[vim.api.nvim_get_current_buf()])
+            autocmd %s * lua require("luasnip").unlink_current_if_deleted()
 			"Remove buffers' nodes on deletion+wipeout.
 			autocmd BufDelete,BufWipeout * lua if Luasnip_current_nodes then Luasnip_current_nodes[tonumber(vim.fn.expand("<abuf>"))] = nil end
 		]] .. (c.config.enable_autosnippets and [[
 			autocmd InsertCharPre * lua Luasnip_just_inserted = true
 			autocmd TextChangedI * lua if Luasnip_just_inserted then require("luasnip").expand_auto() Luasnip_just_inserted=false end
 		]] or "") .. [[
 		augroup END
-		]], c.config.updateevents, c.config.region_check_events))
+		]], c.config.updateevents, c.config.region_check_events, c.config.delete_check_events))
 		if c.config.store_selection_keys then
 			vim.cmd(
 				string.format(